# Angle Measurement - PowerPoint PPT Presentation

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## Angle Measurement

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### Angle Measurement Lesson 2b next – PowerPoint PPT presentation

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Title: Angle Measurement

1
Angle Measurement
• Lesson 2b

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2
Definitions

B
A
I. Ray
1. A ray is the part of a line consisting of one
endpoint and all the points of the line on one
side of the endpoint.
2. A ray goes on forever in one direction without
ending.
3. A ray is named by first stating the endpoint and
then one other point in the direction of the ray.
4. For example, the ray above could be named--

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Ray AB or AB
3
Definitions Cont.

C

B
A
II. Angle
1. An angle is formed by two rays with the same
endpoint.
2. The two rays are called the sides of the angle.
3. The common endpoint is called the vertex.

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4
Definitions Cont.

C
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B
A
II. Angle cont . . .
1. An angle is named a few different ways For our
purposes we will most often use three points to
name an angle.
2. For example, the angle above could be named
?BAC.
• When naming an angle
• The middle letter is always the vertex.
• The first letter is one point on one of the rays.
• The last letter is one point on the other ray.

5
Definitions Cont.

C

B
A
III. Congruence
• Figures that have the same size same shape are
congruent ( ? ).
• Segments are congruent if they are the same
length.
• Angles are congruent if they are the same degree
measure.
• ?ROC is congruent to ?XYZ.
• This can be written, ?ROC ? ?XYZ.

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6
Angle Measurement
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I. Angles are measured using units called
degrees.
1. The symbol for degree is a small raised zero ().
2. We use a protractor to measure angles.

Protractor
40
7
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Angle Measurement cont
1. Angles can be classified according to their
measure.

8
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Angle Measurement cont
Types of Angles
Acute Angle
Obtuse Angle
Angles less than 90 are called Acute Angles.
Angles greater than 90 are called Obtuse Angles.
Right Angle
Straight Angle
Symbol for right angle
180
Angles equal to 180 are called Straight Angles.
Angles equal to 90 are called Right Angles.
9
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Next
10
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Choose the correct measure.
160
20
or
Next
11
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
20
Thats Correct!
20
20
20
20
20
20
Next
12
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
20
How would you classify this angle?
Choose one!
Obtuse
Acute
Right
Straight
Next
13
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Angles less than 90 are called Acute Angles.
20
Thats Correct!
Acute
Next Angle
14
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Next
15
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Choose the correct measure.
130
50
or
Next
16
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Thats Correct!
130
130
130
130
130
130
Next
17
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
How would you classify this angle?
Choose one!
Obtuse
Acute
Right
Straight
Next
18
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Angles greater than 90 are called Obtuse Angles.
Thats Correct!
Obtuse
Next Angle
19
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Next
20
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Choose the correct measure.
118
60
62
78
Next
21
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Thats Correct!
62
62
62
62
62
62
Next
22
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
62
How would you classify this angle?
Choose one!
Obtuse
Acute
Right
Straight
Next Angle
23
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Angles less than 90 are called Acute Angles.
62
Thats Correct!
Acute
Next Angle
24
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Next
25
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Choose the correct measure.
180
90
0
110
Next
26
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Thats Correct!
90
90
90
90
90
90
Next
27
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
How would you classify this angle?
Choose one!
Obtuse
Acute
Right
Straight
Next
28
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Angles equal to 90 are called Right Angles.
Thats Correct!
Right
Next
29
The End Time to move on to the next lesson
30
Back
Angle Measurement cont
Types of Angles
Acute Angle
Obtuse Angle
Angles less than 90 are called Acute Angles.
Angles greater than 90 are called Obtuse Angles.
Right Angle
Straight Angle
Symbol for right angle
180
Angles equal to 180 are called Straight Angles.
Angles equal to 90 are called Right Angles.
31
Angle Measurement cont
Click on the protractor to measure each angle,
then classify the angle as acute, right, obtuse,
or straight.
Sorry Try Again!
Back